The overall goal of this project is to determine the impact of knee osteoarthritis (OA) on physical disability in the elderly. OA increases in prevalence at an age when elders experience deteriorating physical function, yet little is known about the functional impact of knee OA on the elderly. This study will examine that impact while controlling for other factors which affect disability such as age, marital status, living arrangements and medical comorbidities. The Framingham Heart Study cohort will be studied. This group offers several unique advantages in addressing this question: 1) it is a population-based cohort of elderly individuals (mean age 75); 2) knee OA was assessd clinically and radiographically in cohort subjects in 1983-1985; and 3) medical comorbidities and other important variables are contained in the dataset. The specific aims are 1) to ascertain the impact of knee OA and pain on the functional status of elders by cross-sectiona comparison to elders without OA and 2) to determine the longitudinal changes in physical function and knee pain of subjects with OA compared to those without OA. For the cross-sectional study, a secondary data analysis of data obtained at cohort examination 18 (1983-1985) will be performed. It will focus on the impact of knee OA and pain on physical function after adjusting for age, sex, marital status, living arrangements, and specific medical comorbidities, including hear disease, pulmonary disease, stroke, cancer, previous hip fracture, and diabetes. For the longitudinal study, conducted in conjunction with examination 20 (1988-1990), arthritis symptoms and physical function will be reassessed in those who had knee xrays five years earlier and are currently without senile dementia. Exam 20 non-participants will also be contacted and interviewed. Then after comprehensive data abstraction, data analysis will focus on the change in physical function from exam 18 to exam 20 as the outcome. In this analysis, exam 18 knee OA, knee symptoms (including those at exam 20) and other covariates will be tested as predictors of decline in function. This study will provide extensive documentation of the specific functional deficits associated with a very common musculoskeletal problem in the elderly. Results will delineate whether OA is a major factor affecting the decline in function experienced by many older persons. It will also yield new information concerning the link betwen medical diagnoses, symptomatology and functional performance in the elderly.